"Encounters" "All Encounters" ignore zero's

I need to track each person’s performance over the entire night. Let’s say “active” percentage. If someone goes afk and has to miss 3 pulls out of a 3hr raid then their % will be artificially low because it counts those as zero’s. Is there a way to get it to ignore those zero’s and return an accurate % for the fights they were present for? Thanks for the help.